This invention relates in general to suspension systems for use with personal mobility vehicles. In particular, this invention relates to a pivoting suspension system having a torque actuated suspension release mechanism for use with a powered wheelchair.
Power-driven personal mobility vehicles are known in the art and may include vehicles such as, for example, scooters and wheelchairs. Some power-driven personal mobility vehicles, particularly certain configurations of power-driven wheelchairs, are known to include suspension systems to improve ride and stability characteristics. One type of power-driven, personal mobility vehicle is a center drive wheelchair that typically includes a base unit having a frame, two spaced-apart drive wheels, and a plurality of caster wheels. The drive wheels are located generally near the longitudinal center of the base. The caster wheels are usually supported on longitudinally extending suspension arms that may be mounted for pivotal movement relative to the frame. The base may include a suspension system to control the relative movement of the drive wheels and the caster wheels in reaction to obstacles or uneven terrain. In some center drive wheelchair configurations, the drive motor is connected to the caster suspension arm in order to urge the arm and caster wheel over an obstacle. Such drive motor and suspension arm arrangements rely on the torque reaction of the motor to lift the caster wheel over the obstacle. The lifting movement of the suspension arm is typically in an upward direction toward the wheelchair seat. The motor engages the suspension arm and transfers the torque reaction load to the suspension arm, to urge it in an upward direction by the reaction force of the motor.